This invention relates generally to bottle caps, and more particularly concerns frangible plastic caps adapted to sealingly fit over five gallon water bottles; however, the caps are also useful for closure of other type bottle necks.
A prior plastic cap is described in detail in U.S. Pat. No. 3,392,862 to Faulstich. That cap is characterized by certain disadvantages among which are: excessive wall thickness necessary to its construction, but which is wasteful of expensive plastic material; the need for an outward annular protrusion which prevents nested stacking of the caps; inability to effectively seal bottle necks of configuration different from that shown in the patent; and difficulty with rupturing of the cap to enable its rapid removal.